D2D communication is a new technology which enables a direct communication between terminals by multiplexing recourses in a cell thereby enhancing overall performance of a system. D2D communication may include one-to-one communication between terminal devices and one-to-many communication between terminal devices. For example, in a multicast D2D communication scenario as shown in FIG. 10, a user equipment (UE) 1001 functioning as a master UE of a D2D communication performs the D2D communication with multiple other UEs within its communication coverage 1003.
In the 3GPP LTE-A Rel-12 standard, the following two D2D communication modes are defined: the network-assisted D2D resource assignment mode and the resource assignment mode based on autonomous selection by a user initiating a D2D communication. In a case where the user initiating a D2D communication is within the network coverage, both of the above two modes can be used. Otherwise, only the second mode can be used. In a D2D broadcast communication, the master UE firstly transmits a discovery signal to potential D2D target UEs, and then transmits a scheduling assignment signal and a data signal. Upon detection of the discovery signal, a D2D receiving end parses the subsequent scheduling assignment signal and the subsequent data transmission signal using information of the discovery signal.